A permanent fault will cause the line protection to trip again when it recloses in anattempt to energize the line.The auto reclosing function allows a number of parameters to be adjusted.Examples:• number of auto reclosing shots• auto reclosing program• auto reclosing dead times for each shot12.2.2.1 Auto reclosing operation Off and On M12391-91 v6Operation of the automatic recloser can be set to Off and On by a setting parameteror by external control. The setting parameter Operation = Off, or On sets thefunction to Off or On. With the settings Operation = On and ExternalCtrl = On ,the control is made by input signal pulses to the inputs On and Off, for example,from a control system or by a control switch.When the auto recloser is set On, the SETON output is set, and the auto recloserbecomes operative if other conditions such as circuit breaker is closed and circuitbreaker is ready are also fulfilled, the READY output is activated (high). Then theauto recloser is ready to accept a start.12.2.2.2 Start auto reclosing and conditions for start of a reclosing cycle M12391-94 v5The usual way to start an auto reclosing cycle, or sequence, is to start it at selectivetripping by line protection by applying a signal to the START input. Starting signalscan be either, general trip signals or, only the conditions for differential, distanceprotection zone 1 and distance protection aided trip. In some cases also directionalearth fault protection aided trip can be connected to start an auto reclose attempt. Ifgeneral trip is used to start the auto recloser it is important to block it from otherfunctions that should not start an auto reclosing sequence.In cases where one wants to differentiate three-phase auto reclosing dead time, fordifferent power system configuration or at tripping by different protection stages,one can also use the STARTHS input (start high-speed reclosing). When initiatingSTARTHS, the auto reclosing dead time for three-phase shot 1, t1 3PhHS is usedand the closing is done without checking the synchrocheck condition.A number of conditions need to be fulfilled for the start to be accepted and a newauto reclosing cycle to be started. They are linked to dedicated inputs. The inputsare:1MRK 505 393-UEN B Section 12ControlLine differential protection RED650 2.2 IEC 233Application manual
